Oh, you're right - I temporarily forgot that the C runtime compatibility was compiler version specific on Windows. So such an approach *would* require updating the CPython compiler on Windows to at least VS2013 for 3.5. Still, we're likely to want to do that anyway - VS2010 will be as old in 2015 as VS2008 is now, and the latter is already causing hassles for building 2.7 extension modules.